The invention relates to a method for producing cryolite, which takes hydrofluoric acid, clay and sodium chloride as raw materials and comprises steps as follows: (1) hydrochloric acid cryolite mother solution with 20 percent to 25 percent of concentration is used for leaching clay clinker at the temperature of 80 DEG C to 100 DEG C; after the qualification of the leaching, aluminum chloride solution with 40g/l to 50g/l of aluminum iron concentration is obtained after filtration; (2) then, the aluminum chloride solution, the hydrofluoric acid and solid industrial salt are flowed into a synthesizing groove for synthesizing according to the reaction proportion, the material feeding time is 30min to 60min and then the reaction is carried out for 30min to 60min after the material feeding; (3)the synthesized cryolite slurry is filtered for obtaining sand-shaped cryolite runny paste which is washed by hot water and dried to obtain the cryolite product. The method of the invention has the advantages that: (1) the amount of the hydrochloric acid mother solution is small, each ton of cryolite produces 5 square meter of mother solution; wherein, 3 square meter to 4 square meter is recycledand 1 square meter to 2 square meter is byproduct; (2) as the amount of the hydrochloric acid mother solution is small, fluorine and sodium contained are few and the yield coefficient of the main product is high; (3) the byproduct of the hydrochloric acid mother solution has high content, wherein, the content of hydrogen chloride is 20 percent to 25 percent, thus having high utilization value.